Very wise words.
I usually strip the DRM only moments after downloading a new purchase.

Absolutely. My standard "workflow" is:

1. Buy the book from Amazon, sending to "Kindle for PC".
2. Run Kindle for PC to download the book.
3. Copy from "My Kindle Content" into Calibre (thus removing DRM).
4. Send from Calibre to Kindle reading device.

It's much easier to do it via Kindle for PC even if (like me) you do have a Kindle device.

Yes. Otherwise in order to get it into Calibre and use the plug-ins, you have to pick transfer by usb, download the book, import it into Calibre, and then delete it from your desktop. Kindle for PC saves a step.